Paving device



May 24, 1938 G. THVENIN 2,1l8,577

PAVING DEVICE Filed March 11,v 1957 Y Mere/7172 J WOMWVM Patented May 24, 1938 UNITED STATES PATENT OFFICE Application March 11,

1937, Serial No. 130,379

In France March 21, 1936 1 Claim.

The present invention relates to a road paving device which is essentially characterized by the fact that the upper or road surface part of the paving unit is combined with a layer of corresponding form which serves as a support and also for adhesion, and which is adapted to make the connection between the paving units and the roadbed.

The upper surface, of great strength, may consist of metal, and chiefly cast iron or steel, cement, brick, a fused composition` or strong material of any kind, and the adhesive layer may consist of a special bitumen or tar mortar which is quite adhesive and is solid at ordinary temperatures. The adhesive layer may be applied at the factory to the under side of the top piece, thus forming a combination paving device, or the two parts can be put in place separately on the roadbed.

The accompanying drawing shows by way of example an embodiment of the invention.

Fig. l is a plan view of a combination paving unit.

Fig. 2 is a vertical section of the same, on the line A-A of Fig. 1.

In the form of construction represented in the drawing, the paving unit has a polygonal form with reentering angles, and it comprises, on the one hand, an upper metallic part I which has ribs 2 on its under side and is striated at 3 in the upper side, and on the other hand, a layer of yielding material 4 which has been already cast into the metallic part and serves as a backing and an adhesive layer.

In the case in which the two parts are joined together at the factory, the device will thus form a paving device consisting of a single unit, and it thus comprises:

1. The upper part consisting of the strong material which forms the surface adapted for vehicle wheels, and this part will chiefly consist of cast iron.

Z. The lower part, consisting of an adhesive bitumen or tar mortar which forms the elastic layer adapted for adhesion to the roadbed.

The laying of the said paving device, which is adapted to be placed upon a rigid bed such as cement concrete, macadam or an old smooth layer well pounded down, is effected by softening-by heat or by the action of a solventthe under side of the said backing layer, and then applying the device strongly upon the bed, to which it will adhere.

The backing layer is necessarily softened at the place of work, either by heating the device on its under side, in a small oven or directly; or by heating the roadbed by the use of burners, hot air, or like means, to a sufficient temperature in order that when the bituminous mortar of the device makes contact with the roadbed, it will become softened and will thus adhere to the latter; or again, by covering the roadbed with a lm of a suitable solvent.

The paving device is laid by a simple pressure, after it has been put in place.

In the case in which the upper part of the said paving device consists of a substance which is a good conductor of heat, such as cast iron, the paving device may be laid in the dry and the cold state upon the dry roadbed, then strongly heating the top part of the device until the under layer of bituminous mortar softens and adheres to the roadbed.

This method has the advantage of renderingto a certain degree-the rate of laying the pieces independent of the operation of heating.

With the same end in view, it is possible, as a modied method, to cover the concrete of the roadbed with a uniform and regular layer of bituminous mortar, of suitable thickness. This supporting layer is then softened by heating on the spot, either before or after the paving pieces are laid, and if necessary, the said pieces can be forced down and leveled by rolling them by a light road-roller, optionally heated, or by a pounding operation, either mechanical or manual, or by any other suitable method.

In the case in which the two parts are not connected together in advance, backing pieces are prepared at the factory which consist of a yielding material having the same outline and surface as the under side of the top part of the device, and are adapted, after softening to be pressed on the spot between the top part and the bottom part.

The advantages of the said invention consist in the elimination, at the place of work, of all cumbersome and expensive appliances for the preparation of the backing piece, and also in the fact that the preparation at the factory permits of obtaining a material of uniform quality and of regular thickness, and again, in the simplification and the rapidity of the laying operation which result from the same.

I claim:

A process for laying a road paving consisting of a metallic wearing surface and carrying a plastic layer which comprises making in advance composite paving units having an upper metallic face and a relatively thin base of bituminous material, covering the surface of a roadbed with such units in dry and cold state and thereafter heating the metallic upper face to cement individually the units with said roadbed.

GEORGES THVENIN. 

